This is a study to determine the extent to which genetic, maternal, obstetric, pediatric and environmental factors produce eye and visual abnormalities in the Study children; to assess the relative frequency of such anomalies; and, to study the concomitance of visual abnormalities with other sensory and motor neurological and systemic disorders. It includes the analysis between visual abnormalities and outcome variables; anecdotal treatment based on case histories of unusual visual abnormalities; special studies of high-incidence disorders and of concordance in siblings and twins.